A pump device including an impeller and a motor for rotating the impeller is described in Japanese Patent Laid-Open No. 2010-246238. In the pump device, a rotor of the motor includes a sleeve-shaped radial bearing rotatably supported by a fixed shaft, a cylindrical tube shaped magnet disposed on an outer peripheral side with respect to the radial bearing, and a holding member which holds the radial bearing and the magnet. The magnet is provided with four recessed parts in a ring-shaped end face on one side in a rotation center line direction of the rotor. The recessed parts are formed in a circular arc shape with the rotation center line as a center and are provided at equal angular intervals around the rotation center line.
The magnet is attached with a scattering prevention member for preventing the magnet from scattering even if the magnet is broken. The scattering prevention member is a metal member and is provided with a ring-shaped plate part which covers a region on an inner peripheral side of four recessed parts in the ring-shaped end face of the magnet, and four protruded parts which are protruded to the magnet side from an outer peripheral edge portion of the ring-shaped plate part and are inserted into the respective recessed parts.
In this case, when scattering of the magnet is prevented without attaching a dedicated member, the number of components of the rotor is reduced and thus manufacturing costs of a rotor, a motor and a pump device can be reduced.